Norris’s long-standing partner Oliver Russ will leave and join the listed boutique Liontrust Asset Management, which is taking over Argonaut's contract to manage the £169 million European Income and £131 million Enhanced European Income funds. Russ, who manages those funds and will become head of European income at Liontrust, and Norris previously worked together at Neptune Investment Management.

Liontrust said in its own statement it will make a cash payment equal to 1.5% of the European Income business's assets under management as of the completion of the acquisition.

Argonaut paid Standard Life Investments a £836,578 share of its profits in the year to June 2015, according to filings with Companies House, and promised to pay a further £1 million on a discretionary basis subsequent to the year-end.

In a statement on April 7, Norris said: “This ownership agreement demonstrates my belief in Argonaut and my long-term personal commitment to the business."

He told Financial News that he felt more incentivised to invest in the business, now that he controlled its equity.

He said he could be interested in hiring younger managers or analysts willing to buy into his investment philosophy, which backs companies poised to deliver pleasant earnings surprises.

Related

According to a fact sheet published on Argonaut’s website, Norris’ flagship European Alpha fund generated a cumulative return of 204.4% between its launch in May 2005 and January 12, 2016. That compared with 117.2% from the MSCI Europe, excluding UK, index, making the fund the fifth-best performer in its Investment Association peer group of 61 managers.

Norris manages a total of £1.1 billion and contributes significantly to Argonaut’s revenues, which rose from £5.2 million to £6.3 million in the year to June 2015, according to Companies House filings. Operating profits were £3.4 million for the period.

Jonathan Polin, the chief executive of insurer and wealth management group Sanlam, has been named chairman of Argonaut Capital. Norris said Polin played a role in negotiating the restructuring and deal with Liontrust..

• Elsewhere, listed boutique manager Miton Group saw its shares slump 27% to 25p following its statement late on April 6 that two star managers George Godber and Georgina Hamilton have served notice to resign. Miton's assets were £3 billion as of March 31 and the value of Godber and Hamilton's UK Value Opportunities Fund was £869 million. In a statement Miton said its focus would be on "looking after the best interests of its clients" as it recruited their replacements.

CORRECTION: This story has been amended to remove the reference to Russ as co-founder of Argonaut